Multi-lock clamping chain and method



Aug. 9, 1966 w. LEW] 3,265,265

MULTI-LOGK CLAMPING CHAIN AND METHOD Filed March 19, 196

United States Patent 3,265,265 MULTi-LOCK CLAMPING CHAIN AND METHODWilliam Lewi, 1840 Relyea Drive, Long Island City, N.Y. Filed Mar. 19,1964, Ser. No. 353,202 3 Claims. c1. 226-2) This invention relates toopposed locked together moving chain links and more particularly to suchlinks having a thermoplastic film clamped therebetween so that variousoperations may be accurately performed thereon without a stress andstrain distortion of said clamped film.

As shown and described in Patent US. 2,896,943 a continuousthermoplastic film is clamped between co-acting moving top and bottomU-shaped frames.

Such a clamping action is quite satisfactory for relatively thick films.However, modern films made from Mylar may be as thin as 0.001 inch andto rigidly clamp such thin films between the planar flat surfaces areasof the U-shaped frames and against the action of dies, etc., is verydifficult.

Accordingly, it is an object of this invention to increase the clampingor seizure pressure or force on the film disposed between the U-shapedclamps.

It is another object to lockingly seize the film disposed between theU-shaped frames at preselected points along the periphery of the frames.

These and other objects of this invention will become apparent uponreading the following descriptive disclosure taken in conjunction withthe accompanying drawing in which;

FIG. 1 is a schematic partial view of a co-acting clamping dual chainhaving U-shaped links, showing the manner of feeding a plastic filmtherebetween,

FIG. 2 is a transverse section view taken along line 2-2 of FIG. 1 andshowing a pair of opposed co-acting threaded set screws, broken away inpart, disposed in threaded boreholes and the manner of locking the filmbetween said opposed set screws, and

FIG. 3 is a view similar to that of FIG. 2 wherein the opposing setsscrews are modified so as to perforate the fihn to effect a perforatedmodified locking therebetween.

Where thin film of thermoplastic film material or where easily stressdistorted thermoplastic film is used, it is important that the filmclamped between the U-shaped clamps does not shift upon being subjectedto the stress of heated die molding, loading with merchandise, sealingwith a cover sheet, etc. as the film passes through these variousstations of operation thereon.

The chain is operated in timed intermittent movement and the variousoperations performed on the film as it comes to rest are of a precisioncharacter, so that any shifting of the film is highly undesirable.

To prevent such shifting of the film according to this invention each ofthe U-shaped clamps are provided with a plurality of identical threadedboreholes identically spaced-apart on the members constituting theU-shaped frames. At least two suitably spaced boreholes are made in eachsection of the three elements constituting the U-shaped frame.

As shown in FIG. 2, the boreholes of the top clamp are disposedprecisely over the boreholes of the bottom clamp so that pairs ofco-acting set screws disposed suitably in said clamps meet in a precisepredetermined manner to effect a locking seizure on the film between theopposing set screws.

Turning now to the drawing, a top and a bottom 11 chain, each made ofmating identical U-shaped frames 12 are provided with a continuous film13 disposed in clamped relationship therebetween as set forth in US.2,896,943.

According to this invention each of the frames 12 are modified byproviding each of the three structural elements of the U-shaped framewith at least two threaded boreholes 14. The boreholes 14 in the topframe 12 are disposesd so as to be aligned with the boreholes 14 of thebottom frames 12. All the frames 12 therefore are of like construction.

As shown in FIG. 2, a mated male and female pair of set screws isdisposed in opposing pairs of boreholes 14. The male set screw 15 in themodification of FIG. 2 is provided with a blunt nose 16 and the femaleset screw 17 is provided with a round or blunt cavity 18 to receive theblunt nose and to pinch the film 13 therebetween with out perforatingsaid fihn.

As shown in FIG. 2, the male and female set screws are preferably eachthreaded in their respective boreholes so as to each protrude suitablybeyond the flat plane of the frame 12. Thus each pinched portion of thefilm 13 is provided with an annular channel by the rim 19 of the femaleset screw and also with a central dome portion by set screw elements 16and 18.

Thus the film 13 is locked together at at least two spaced-apart pointson each side of the rectangular portion of the film clamped within aU-shaped frame thereby preventing movement of the film during the hotdie forming operation, etc. thereon.

In the set screw modification of FIG. 3, the male set screw 20 isprovided with a sharp point 21, and the female set screw 22 is providedwith a co-acting sharply pointed recess 23 so as to effect a perforationon the film and thereby lock the pinched film 13 around the metal point21 to prevent a pulling away therefrom.

In FIG. 3 only the male point 21 is made to protrude beyond the flatsurface of the frame 12 so that channeling of the film around the pointneed not be present. However, such channeling of the film around thepoint 21 can be had by suitable screw thread adjustment of the femaleset screw 22.

It is thus seen that because of the threading of both set screws of amating pair of predetermined channel or non-channel locking or pinchingis possible as well as effecting the degree of seizure that is desiredupon the lockingly pinched film.

Thus the set screw pairs are changeable in their coacting operative endsand they are adjustable in their boreholes one to the other to effect awide range of seizure pressure and also to effect a channeled seizure ofgreater seizure area where desired. Thus film of various thickness andquality are accommodated in this invention.

The set screws are provided on their adjustment ends with conventionalwells 24 to receive conventional Allen wrenches. Other conventional slotmeans of obtaining threaded adjustment may be employed on the setscrews.

It is therefore seen that the planar clamping action of the chains asset forth in the Patent 2,896,943 is improved in this invention by aselective and localized clamping action within the planar clamping area,said localized clamping being of a locking nature and of greater seizureforce than in the planar area so as to pinch with distortion the film inthe localized area.

The degree of pinching or locking pressure and the kind of distortion isselective in nature and also of a predetermina'ble quality as to beingchannel-like or nonohannel-like and also as to being perforated orotherwise.

Fundamentally, the method of clam-ping of this invention comprises largearea of normal planar clamping co-acting with a plurality of localizedclamping areas having a strong locking function and disposed within saidplanar clamping areas. This localized locking effect is adjustable bothas to degree of clamping or seizure pressure and also as to kind, forexample, whether nonperforated or perforated.

This invention has been illustrated by way of many embodiments thereofbut it is not limited thereto.

I claim:

1. In an opposed identical mating U-shaped top and bottom pair of hingedcontinuously moving planar surface clamping frames for effecting aperipheral clamping action about an area of a moving sheet or plasticfilm clamped therebetween the improvement comprising said mating pairsof frames having a plurality of spaced-apart opposed suitably threadedboreholes transversely therethrough disposed in axial alignment, andthreaded coactiug male and female set screws disposed completely inmating relationship in said opposed pairs of boreholes, wherebyadjustment of said set screws to pinchingly seize said film therebetweeneffects localized locking clamping action of greater seizure force tothe already clamped surfaces of said frames.

2. The pair of frames of claim 1 wherein the male set screw is providedat its inner end with a blunt conical configuration and the co-actingfemale set screw is provided with a mating blunt cavity, whereby anontearing locking pinching action is effected on the film disposedtherebetween.

3. The method of peripherally locking moving clamping areas of a movingfilm of thin plastic between pairs of opposed moving planar peripheralU-shaped frames comprising peripheral area clamping said moving film tosaid moving frames to efiect large area planar edge rectangular seizureclamping and spot spaced-apart setscrew clamping said film within saidplanar clamping to eifect a plurality of small area clampings of slipproof locking force within said large area of planar seizure clamping.

References Cited by the Examiner UNITED STATES PATENTS Re. 23,17111/1949 Borkland. 2,230,189 1/1941 Ferngren. 2,896,943 7/1959 Lewi226-172 3,011,295 12/1961 Brugger 53372 M. HENSON WOOD, JR., PrimaryExaminer.

I. N. ERLICH, Assistant Examiner.

1. IN AN OPPOSED INDENTICAL MATING U-SHAPED TOP AND BOTTOM PAIR OFHINGED CONTINUOUSLY MOVING PLANAR SURFACE CLAMPING FRAMES FOR EFFECTINGA PERIPHERAL CLAMPING ACTION ABOUT AN AREA OF A MOVING SHEET OR PLASTICFILM CLAMPED THEREBETWEEN THE IMPROVEMENT COMPRISING SAID MATING PAIRSOF FRAMES HAVING A PLURALITY OF SPACED-APART OPPOSED SUITABLY THREADEDBOREHOLES TRANSVERSELY THERETHROUGH DISPOSED IN AXIAL ALIGNMENT, ANDTHREADED COACTING MALE AND FEMALE SET SCREWS DISPOSED COMPLETELY INMATING RELATIONSHIP IN SAID OPPOSED PAIRS OF BOREHOLES, WHEREBYADJUSTMENT OF SAID SET SCREWS TO PINCHINGLY SEIZE SAID FILM THEREBETWEENEFFECTS LOCALIZED LOCKING CLAMPING ACTION OF GREATER SEIZURE FORCE TOTHE ALREADY CLAMPED SURFACES OF SAID FRAMES.